Transport mechanism



April 19, 1966 E. w. JENSEN TRANSPORT MECHANISM Filed June 17, 1963 m mM W R A w E WWW Y B A TTOR/VEYS United States Patent 3,246,823 TRANSPORTMECHANISM Einar W. Jensen, Rochester, N.Y., assignor to Eastman KodakCompany, Rochester, N.Y., a corporation of New Jersey Filed June 17,1963, Ser. No. 288,220 8 Claims. (Cl. 226188) This invention relates toa transport mechanism and, more particularly, to a transport arrangementoperable to convey with equal facility strip films or sheet materialboth subject to length variation considerations.

. In transport mechanisms for self-threading and transporting flexiblematerial such as photographic film or paper through a processingsolution, the material being processed expands in all directions. Sincethere is no opportunity for increasing the spacing between the transportmechanisms, in transport mechanisms of the type in which i the materialis interposed between guide and driving rollers of predetermined spacedintervals, slack will tend to develop in the material as it expands. Inthe case of mating guide rollers, this slack'tends to be detrimental inthat the transported material will tend to weave from side to side. Suchweaving from time to time will result in creases or mistracking andthereby damage or loss of the film material. The developing of slack intransported flexible material is eliminated in the present invention byproviding a continuous, yet flexible drive arrangement in turn-aroundportions ofthe equipment. T

One of the primary objects of the present invention is to provide animproved transport mechanism for conveying flexible material oftwosubstantially different types, one being continuous webbing and theother being arelatively short sheet material.

A more specific object of this invention is to provide a simpleandreliable transport mechanism operable by a soft,over-driving clutch"such that a minimum speed is assured, but the speed automaticallyincreases'to match the speed of a webbing'being transported.

-In accordancewith 'one embodiment of myinvention, a -plurality ofco-operating rollers transport flexible material at a constantpredetermined velocity-to a master roller assembly arranged to'changethe line of travel of the material. Because of expansion problems, themaster roller is spaced apart from a pluralitycf peripheral guiderollers, which are driven at a speed no less than that of theco-operating rollers. The master roller is, however, driven at a lowerspeed by a unidirectional clutch which allows the flexible material toincrease the speed of the master roller should the expansion characterthereof so dictate.

' The 'subiect' matter which is'regarded as my invention is particularlypointed out and distinctly claimed in the concluding portion of thisspecification. The invention, however, as to its organization andoperation together with further objects and advantages thereof, willbest be understood by reference to the following description taken inconnection with the accompanyingdrawing in which: FIG; 1 is a schematicview partially in cross-section of atransport mechanism in accordancewith the present invention; 1 i 1 Y a FIG. 2 is an enlarged detail viewillustrating the present invention;'and

FIG. 3 is a cross-sectional view taken along the line 3-3 of FIG. 2. t gReferring now to the drawing, wherein like numbers referto similarparts, I have illustrated in FIG. 1 a wet portion of a'processingequipment including at least three separate tanks 10, 1-1 and 12 whichcontain fluids such as developer, stop bath and fixer. Within thesetanks and over the top of the spacing therebetween, I have provided aplurality of rollers drivable by a speed-regulated motor "ice 14.Transport rollers within each of the tanks may be coupled to drivinggears 16 and 17 by a driving means such as a chain 18 which engages asprocket on one end of each of therollers 20 within the tanks to drivesubstantially all of the rollers so that they have equal and constantsurface speeds. Equal surface velocities are attainable, by way ofexample, when the sprocket drives have an effective diameter equal tothe surface diameter of the rollers themselves.

As is shown more clearly in FIG. 2, I prefer that the vertical transportrollers 20 be of substantially identical diameters to simplify thedriving ratios. However, I have found that the turn-around central ormaster roller 22 should be of a substantially larger diameter to conveyvarious sheets of flexible material, such as film sheets 24, 25 and 26from one line of co-operating transport rollers 24) to a next Withoutexcessive bending of thefiexible material.

As is explained in some detail in the U.S. Patent No. 3,072,310, issuedin the name of Charles J. Kunz, January 8, 1963, and assigned to theassignee of the present invention, the flexible material passes betweenthe rollers 20, being guided by impingement upon and engagement on thesurfaces thereof during its threading and transport through the solutionin the tanks. Also, as explained in that patent, turn-aroundself-threading of the flexible material is accomplished by the masterroller 22 and spacedapart smaller rollers 28 co-operating with a pair ofguide shoes 29 which divert the sheets laterally of their line of motionso that they follow the curvature of the master roller 22. In apreferred embodiment, each of the rollers 28 are grear driven by themaster roller 22 to have surfacevelocities no less than that of therollers 20. p v

. Also in accordance with one particular embodiment of the presentinvention, an additional pair of rollers 30 is provided to assist in theguiding of the film sheets as they leave a slightly enlarged roller 32which changes the direction of the sheets 2426 so that they are easilyconveyed around the turn-around mechanism. Because of spacing problems,I prefer to drive the pair' of rollers 3tlby a pair of belts 33 drivenby the rollers 28. The drive ratios are selected so that the surfacevelocities of the nearest rollmaster roller 22, to facilitate handlingboth continuous webs of flexible material such as 50 feet or more, andshort sheets 26 of 5 inches or less. If the masterroller 22 ispositively driven at the same surface velocity as the rollers 20, thedimensional instability of continuous Webbing filmcauses considerablebuild-up of tension in the region of the turn-around. This problem makesmost difficult the transport of continuous webbing by a posi-- tivedrive. A roller arrangement which overcomes this problem .by removingdrive of the master roller 22 presents a serious problem of stoppage ofthese rollers when one attempts to self-thread therethrough film sheetshaving a length less than about 5 inches. Such a film sheet tends topass only part way around the enlarged master roller 22, whereupon theroller 22 stops until a next sheet arrives to drive it. The resultingoverlapping of sheets tends to cause serious damage to'partiallydeveloped films. v

In accordance with the present invention, I have provided a drivingsprocket gear 34 shown (partially in phantom in FIG. 2) in FIG. 3 havinga slightly larger eflective diameter than that of the master roller 22.Thus, the velocity of the chain 18 driving the sprocket gear 34 isslightly (about 2%) greater than the surface velocity of the masterroller 22. However, the rollers 28 and 30 are driven at surfacevelocities greater than that of the roller 22. Such an arrangementallows the dimensional instability of elongated film materials to becompensated for by the slightly reduced surface speed. If no reductionin velocity is called for by the exigencies of a particular film strip,the outer rollers 28 will drive the film at full speed.

The driving coupling between the sprocket gear 34 and the master roller22 is a unidirectional clutch 36 arranged so that it provides a softoverdrive feature. As a result, when continuous Webbing engages thesurface of the master roller 22, it may drive this surface at velocitiessubstantially equal to the surface velocities of the rollers 20, wherebythe driving coupling of the clutch 36 by the sprocket gear 34 and theroller 22 is disengaged. On the other hand, when the film sheets such as26 pass through the region of the enlarged master roller 22, they willbe driven along the desired transport path by engagement of theunidirectional clutch 36 so that stoppages as set forth above may notoccur.

Thus, the chain 18 and the sprocket gear 34 tend to underdrive themaster roller 22, and the longer sheets or Webs of flexible material(films 24) overdrive the overrunning clutch 36 to surface speed of themaster roller 22 as great as that of the rollers 20.

While I have shown and described particular embodiments of the presentinvention, other modifications may occur to those skilled in this art. Iintend, therefore, to have the appended claims cover all modificationswhich fall Within the true spirit and scope of my invention.

I claim:

1. In a conveyor arrangement for transporting and guiding at apredetermined lineal velocity a flexible material subject to dimensionalinstability considerations, a transport mechanism comprising:

a master roller;

a drive means for assuring a peripheral surface velocity of said masterroller only slightly less than the predetermined lineal velocity of theflexible material;

a plurality of guide means spaced apart from and disposed around saidmaster roller for guiding the flex ible material therearound; and

a unidirectional clutch coupling said master roller to said drive meansso that when the flexible material tends to travel therearound atvelocities less than the driven velocity, said clutch drives theflexible material, and when the flexible material continues to travel atthe predetermined velocity, said clutch slips.

2. A transport mechanism as set forth in claim 1 wherein the drive meansincludes a chain and a sprocket with said chain having substantially thesame velocity as the flexible material approaching said master roller,and said sprocket has an eifective diameter about 2% greater than thatof said master roller.

3. In a conveyor arrangement for transporting and guiding at apredetermined lineal velocity a flexible material subject to dimensionalinstability considerations, a transport mechanism comprising:

a master roller;

a drive means for assuring a peripheral surface velocity of saidmasterroller only slightly less than the predetermiend lineal velocityof the flexible material;

a plurality of guide means including subservient rollers spaced apartfrom and disposed around said master roller for guiding the flexiblematerial therearound;

a unidirectional clutch coupling said master roller to said drive meansso that when the flexible material tends to travel therearound atvelocities less than 4- the driven velocity, said clutch drives theflexible material, and when the flexible material continues to travel atthe predetermined velocity, said clutch slips; and

means for driving said subservient rollers at surface velocities greaterthan that of said master roller.

4. A transport mechanism as set forth in claim 3 wherein said drivingmeans of said subservient rollers includes gearing having gear ratiossuch that the surface velocity of said subservient rollers is no lessthan the predetermined lineal velocity.

5. A transport mechanism for a Web or sheets of flexible material havingthe property of expanding during transport, comprising:

a rotatable master roller having a peripheral surface drivable totransport the material;

a plurality of guide rollers disposed around the periphery of saidmaster roller and spaced apart therefrom;

drive means for driving said master roller to have a surface velocityslightly less than the velocity of the flexible material as itapproaches said master roller; and

an overrunning clutch coupling said drive means to said master rolleronly when the flexible material is not driving said master roller at aspeed greater than that developed by said drive means.

6. A transport mechanism as defined in claim 5 wherein said guiderollers are drivably coupled to said master roller by gearing havingratios so that the surface velocity of said guide rollers is equal tothe velocity of the flexible material when said drive means iseifectuating rotation of said master roller.

7. A transport mechanism for a web or sheets of flexible material havingthe property of expanding during transport, comprising:

a rotatable master roller having a peripheral surface drivable totransport the material;

a plurality of first guide rollers disposed around the periphery of saidmaster roller and spaced apart therefrom;

a plurality of drive rollers positioned to present the material to saidmaster roller and receive it therefrom with a main portion thereofdefining parallel paths of the flexible material which are spaced apartless than the effective diameter of said master roller and includingroller means adjacent to said master roller for expanding the paths ofthe flexible material to engage the periphery of said master roller;

drive means for driving said master roller to have a surface velocityslightly less than the velocity of the flexible material as itapproaches said master roller; and

an over-running clutch coupling said drive means to said master rolleronly when the flexible material is not driving said master roller at aspeed greater than that developed by said drive means.

8. A transport mechanism as defined in claim 7 hav ing other guiderollers positioned between said master roller and said roller means toguide the flexible material therebetween said other guide rollers beingdrivably coupled to said first guide rollers to have a surface velocityequal to that of said first guide rollers.

References Cited by the Examiner UNITED STATES PATENTS 2,167,357 7/1939George 226--156 X 2,966,746 1/1961 Mellbin 2261l9 X 3,072,310 1/1963Kunz 226188 ROBERT B. REEVES, Primary Examiner.

C. A. AOUSSAT, Assistant Examiner.

1. IN A CONVEYOR ARRANGEMENT FOR TRANSPORTING AND GUIDING AT APREDETERMINED LINEAL VELOCITY A FLEXIBLE MATERIAL SUBJECT TO DIMENSIONALINSTABILITY CONSIDERATIONS, A TRANSPORT MECHANISM COMPRISING: A MASTERROLLER; A DRIVE MEANS FOR ASSURING A PERIPHERAL SURFACE VELOCITY OF SAIDMASTER ROLLER ONLY SLIGHTLY LESS THAN THE PREDETERMINED LINEAL VELOCITYOF THE FLEXIBLE MATERIAL; A PLURALITY OF GUIDE MEANS SPACED APART FROMAND DISPOSED AROUND SAID MASTER ROLLER FOR GUIDING THE FLEXIBLE MATERIALTHEREAROUND; AND A UNIDIRECTIONAL CLUTCH COUPLING SAID MASTER ROLLER TOSAID DRIVE MEANS SO THAT WHEN THE FLEXIBLE MATERIAL TENDS TO TRAVELTHEREAROUND AT VELOCITIES LESS THAN THE DRIVEN VELOCITY, SAID CLUTCHDRIVES THE FLEXIBLE MATERIAL, AND WHEN THE FLEXIBLE MATERIAL CONTINUESTO TRAVEL AT THE PREDETERMINED VELOCITY, SAID CLUTCH SLIPS.